A received signal strength indicator (RSSI) is defined at the antenna input connector, but it is not fully specified, because there are no unit definitions and no performance requirements, such as accuracy or testability. It is not possible to extract meaning from a comparison of RSSIs from different stations and from different channels/physical layers (PHYs) within the same station. RSSI may have limited use for evaluating access point (AP) options within a station, such as a wireless local area network (WLAN) station, and within a given PHY, but is not useful for evaluations between PHYs. RSSI is rescaled between direct sequence spread spectrum (DSSS) and orthogonal frequency division multiplex (OFDM) PHYs. RSSI is clearly not useable by network management for handoff or load balancing. RSSI from one station does not relate to RSSI from any other station. In high interference environments, RSSI is not an adequate indicator of desired signal quality, since it indicates the sum of:
desired signal+noise+interference powers.